diff --git a/shaders/simple.frag b/shaders/simple.frag
index 317459d..48ebcb1 100644
--- a/shaders/simple.frag
+++ b/shaders/simple.frag
@@ -169,9 +169,10 @@ float getRiverDistance(vec2 p, int mask) {
     }
 }
 
-float getRoadDistance(vec2 p, int mask, vec2 tileCenterWorld, float amp) {
-    float h1 = fract(sin(dot(tileCenterWorld, vec2(12.9898, 78.233))) * 43758.5453);
-    float s1 = (h1 > 0.5) ? 1.0 : -1.0;
+float getRoadDistance(vec2 p, int mask, int ix, int iy, float amp) {
+    // Exact integer parity per hex tile: completely immune to floating-point interpolation jitter across scanlines!
+    int parity = (ix * 3 + iy * 5) & 1;
+    float s1 = (parity == 0) ? 1.0 : -1.0;
 
     int edges[6];
     int count = 0;
@@ -363,63 +364,44 @@ void main() {
     vec4 landColor = mix(nonSnowLand, snowColor, snowWeight);
 
     // 6b. Road Texture Integration (blended directly into the tile surface texture)
-    if (hasRoad == 1 && oceanWaterFac < 0.95) {
+    if (hasRoad == 1) {
+        // Recover exact integer grid indices of the tile center (spacing is 0.75 in X and 0.43287992 in Y)
         vec2 tileCenterWorld = vWorldPos.xy - fragVert.xy;
+        int ix = int(floor(tileCenterWorld.x / 0.75 + 0.5));
+        int iy = int(floor(tileCenterWorld.y / 0.43287992 + 0.5));
         float amp = max(0.0, roadMeander);
 
-        float rawRoadDist = getRoadDistance(fragVert.xy, roadMask, tileCenterWorld, amp);
         float rScale = max(1.0, roadTextureScale);
         vec2 uvRoad = vWorldPos.xy * rScale;
 
+        // Sample textures in uniform control flow (before any fragment-dependent branch) to avoid mipmap derivative glitches
         vec3 soilTex  = texture(texSand, uvRoad).rgb;
-        vec3 stoneTex = texture(texRock, uvRoad * 1.25).rgb;
-        float pebbleRelief = mix(soilTex.r, stoneTex.r, 0.5) - 0.5;
+        vec3 saharaTex = texture(texSahara, uvRoad * 0.9).rgb;
+        float fineGrain = (mix(soilTex.r, saharaTex.r, 0.5) - 0.5) * 0.18;
 
-        // Very subtle micro-edge grain (0.0018) so the road has crisp, clean borders
-        float dRoad = max(0.0, rawRoadDist + pebbleRelief * 0.0018);
+        float rawRoadDist = getRoadDistance(fragVert.xy, roadMask, ix, iy, amp);
 
-        float rCore = max(0.014, roadRadius);
-        float rOuter = rCore + max(0.006, roadBorderWidth);
+        float rCore = max(0.012, roadRadius);
+        float rOuter = rCore + max(0.005, roadBorderWidth);
 
-        // Crisp road deck and distinct dark casing/curb
-        float roadCoreFac  = 1.0 - smoothstep(rCore * 0.80, rCore, dRoad);
-        float roadTotalFac = 1.0 - smoothstep(rOuter * 0.82, rOuter, dRoad);
+        float roadCoreFac  = 1.0 - smoothstep(rCore * 0.65, rCore, rawRoadDist);
+        float roadTotalFac = (1.0 - smoothstep(rCore, rOuter, rawRoadDist)) * (1.0 - oceanWaterFac);
 
         if (roadTotalFac > 0.001) {
-            vec3 roadSurf;
-            if (roadType == 1) {
-                // Stone / Cobblestone road: bright paved stone with crisp dark curb
-                vec3 cobbleSurface = roadColor * (0.88 + 0.35 * pebbleRelief);
-                vec3 stoneCurb     = roadBorderColor * (0.85 + 0.25 * pebbleRelief);
-                roadSurf = mix(stoneCurb, cobbleSurface, roadCoreFac);
-            } else if (roadType == 2) {
-                // Railroad: dark gravel ballast bed with steel twin rails
-                vec3 ballast = roadBorderColor * (0.85 + 0.35 * pebbleRelief);
-                float railLine = smoothstep(rCore * 0.38, rCore * 0.48, rawRoadDist)
-                               * (1.0 - smoothstep(rCore * 0.56, rCore * 0.68, rawRoadDist));
-                vec3 steelRail = vec3(0.75, 0.78, 0.82);
-                vec3 innerBed  = mix(roadColor * (0.85 + 0.30 * pebbleRelief), steelRail, railLine);
-                roadSurf = mix(ballast, innerBed, roadCoreFac);
-            } else {
-                // Dirt / Country road: warm sandy-ochre packed earth with two subtle cart wheel tracks & dark curb
-                float wheelRut = smoothstep(rCore * 0.30, rCore * 0.48, rawRoadDist)
-                               * (1.0 - smoothstep(rCore * 0.55, rCore * 0.72, rawRoadDist));
-                vec3 brightDeck = roadColor * (0.92 + 0.32 * pebbleRelief);
-                vec3 darkCurb   = roadBorderColor * (0.85 + 0.25 * pebbleRelief);
-                vec3 trackedDeck = mix(brightDeck, darkCurb, wheelRut * 0.35);
-                roadSurf = mix(darkCurb, trackedDeck, roadCoreFac);
-            }
+            vec3 centerTone = clamp(roadColor * (1.0 + fineGrain), 0.0, 1.0);
+            vec3 borderTone = clamp(roadBorderColor * (1.0 + fineGrain * 0.7), 0.0, 1.0);
+            vec3 roadSurf   = mix(borderTone, centerTone, roadCoreFac);
 
-            // If crossing a river, render a crisp bridge deck and suppress river water under the bridge
+            // If crossing a river, render a bridge deck and suppress river water under the bridge
             if (riverWaterFac > 0.01) {
                 vec3 bridgeCol = (roadType >= 1)
-                    ? vec3(0.72, 0.70, 0.66) * (0.90 + 0.25 * pebbleRelief)
-                    : vec3(0.68, 0.48, 0.28) * (0.90 + 0.25 * pebbleRelief);
+                    ? vec3(0.72, 0.70, 0.66) * (1.0 + fineGrain)
+                    : vec3(0.68, 0.48, 0.28) * (1.0 + fineGrain);
                 roadSurf = mix(roadSurf, bridgeCol, riverWaterFac);
                 waterFac *= (1.0 - roadTotalFac * 0.98);
             }
 
-            float blendAlpha = roadTotalFac * clamp(roadOpacity, 0.0, 1.0) * (1.0 - oceanWaterFac);
+            float blendAlpha = roadTotalFac * clamp(roadOpacity, 0.0, 1.0);
             landColor.rgb = mix(landColor.rgb, roadSurf, blendAlpha);
         }
     }